This interesting circuit uses a sodion valve that we have already described in an article on the website. The circuit uses several batteries for power. The phone is of high impedance.
This circuit was found in Motorola's Linear Interface ICs of 1993. The integrated circuit used is not...
Using Linear Technology's LTC4252-1, this circuit was found in a 2005 manual. The circuit makes use of...
The frequency of this oscillator depends on R and C (see math section for electronics). The...